Spring mounting for vibratory tables and the like



gamma and ammunswan-n EXUWW S pt- 3, 1968 w. J. SCHULTZ 3,399,857

ATORY TABLES AND THE LIKE SPRING MOUNTING FOR VIBR Filed Jan. 16, 1967 FIG. I

FIG. 2

E 7 OR W. J. SCHULTZ all...

3,399,857 SPRING MOUNTING F OR VIBRATORY TABLES AND THE LIKE William J. Schultz, El Paso, Tex. (8405 W. Winslow Road, Palos Park, Ill. 60464) Filed (Ian. 16, 1967, Ser. No. 609,464 1 Claim. (Cl. 248-350) ABSTRACT OF THE DISCLOSURE nah-NW Background of the invention The art abounds with work tables in which an upper table or work member is resiliently sustained by a floormounted support and is caused to move by vibration or other means for the compaction, settling etc. of particulate, viscous and other material. One type of such device is known as a vibrating table in which the table top is mounted on the support by means of a plurality of upright coil springs and carries a vibrator which imparts relatively high-frequency vibration to the top which, because of its spring mounting, may move universally but generally in a substantially horizontal plane. Another form of such device is the jolt table in which a similar arrangement is used but the springs are pre-loaded in tension to draw the table downwardly against stops on the support. A linear actuator carried. by the support has a vertically reciprocating push rod connected to the table top and operates cyclically to push the top upwardly away from the stops and against the tension of the springs and then to release the table top so that the springs return it sharply against the stops to create the necessary jolting action.

In both types of tables the springs are anchored at opposite ends respectively to the support and top and the basic problems encountered occur because of premature failure of the anchors, subjected as they are to the forces created during operation of the table. Most prior art connectors are of the metallic threaded plug type, screwed into the spring coils, but these become loose and noisy and often cause fatigue in the spring and wear in the fasteners. Also, when a connector or spring of the above character breaks, it is difiicult to separate the plug and its spring because the spring tends to tighten its grasp on the plug as it is turned.

Summary of the invention The invention provides a plurality of improved con nector means, one for each end of each spring and including a plug-like element closely coaxially received in the end turns of the spring and of such construction that when it is subjected to an axially compressive force it expands diametrically to grip the spring coils. The plug is centrally apertured and abuts the proximate face of the support or table and a threaded fastener is passed through the plug into engagement with the table or support and is tightened to expand the plug. These fasteners may be subsequently adjusted in the event that they become loose during operation of the table, are quiet in operation and are easily installed and removed. By selection of the elastomer material as to density, resilience, deformability etc. and depending upon initial unstressed shapes and ultimate force of compression, the relationship of the element 30 ten t;-

Patented Sept. 3, 1 968 to the spring may be varied. For example, a simple cylin drical element would expand under relatively light compression to a somewhat doughnut shape and under heavier compression the material of the element would tend to flow into the grooves between spring coils. By giving the element a somewhat toroidal initial shape as here the latter characteristic could be enhanced.

Description of the drawings FIGURE 1 is a fragmentary elevation of a typical vibrating table;

FIGURE 2 is a similar view of a typical jolt table;

FIGURE 3 is an enlarged sectional view showing a spring and its connector means;

FIGURE 4 is an enlarged fragmentary view illustrating the character of the installation at one end of the spring before completed; and

FIGURE 5 is similar to FIGURE 4 but shows the changes effected in the plug when installation is complete.

Description of the preferred embodiment Although the devices of FIGURES l and 2 are different, they may be regarded as the same in the respects important here and therefore the basic parts will be numbered alike. The support member 10 may be any suitable floorsupported stand having a plurality of upper horizontal members, one of which is shown at 12, forming a rectangular frame. The movable work member 14 may be a horizontal flat or plate-like member capable of supporting the burden to be vibrated or jolted. The work member 14 is sustained by the stand or support through the medium of a plurality of resilient units 16. In a typical situation there will be four such units, one at each corner of the device. More units could be used, depending upon the size of the table etc.

In the FIGURE 1 arrangement, a vibrator 18 is secured to the underside of the work member 14 and is capable of importing relatively high frequency vibrations to the member, largely back and forth or from right to left as seen in the drawing, the units 16 yielding transverse to their axes to permit this movement. There will of course be multi-directional components introduced into the units 16 because of the weight of the burden carried by the member 14, inertia, unbalance etc. so that the member can have universal movement, all of which imparts forces of various types and magnitudes to the units 16, requiring that they be well designed, constructed and installed if they are to perform efficiently and over long periods.

The vibrator 18 may be of any well known type, familiar to those versed in the art and therefore need not be shown in detail.

In the case of the jolt table (FIGURE 2) the units 16 are pre-tensioned to draw the member 14 down against a plurality of rigid stops 20. A linear actuator 22 is rigidly attached to the support 10 and has a vertically reciprocating push rod 24 connected to the underside of the member 14. This actuator, like the vibrator, is also familiar to those versed in the art and need not be shown in detail. Its operation involves cyclical reciprocation of the push rod 24 so as to push the member 14 away from the stops 20 and to then release the member so that it is brought joltingly back against the stops by the units 16. Although the frequency of the jolts in the jolt table is not as high as that capable of being achieved in the vibrat ing table, the spring and connector problems are substantially the same and the same solution to these problems, according to the present invention, works in both cases.

Each unit 16 comprises a coiled steel spring 26 whose coils or turns at each of its opposite ends 28 may be rela tively close together to closely and coaxially receive a circular connector element 30 having a central through opening 32 and whose annular outer surface 34 is gen= 3 erally of toroidal configuration. The element 30 is of such construction and nature that, when subjected to axial compression, its outside diameter increases uniformly about the surface 34. Rubber or other comparable elastomer has been found to be suitable material of which to make such elements.

Each connector element 30 is mounted to its associated member 112 or 114 by a threaded fastener means such as a bolt 36 passed through a registering member aperture 38 and through the element hole 32 and fitted with a washer 40 and nut 42. The washer is preferably large enough to confine the element face on which it seats, and when the bolt is tightened or tensioned the element be comes axially compressed and diametrically larger so as to grip the end coils 28 of its spring 26. Compare FIG- URES 4 and 5. Each spring is thus securely connected at its ends to the members 12 and 114.

If the spring connections should become loose during operation, the bolts may be easily tightened to secure the proper element-spring relationship. The comparative softness of the element relative to its spring eliminates noise. The element does not fatigue the spring as do the prior art metallic plugs. In the event of a failure in any part of a unit, the element is easily removed because loosening of the bolt enables the element to recover at least part of its FIGURE 4 condition so that it can be readily withdrawn from its spring.

I claim:

ll. In a material'handling table or the like, includingsupport and work members arranged in superposed relation to each other, a plurality of coil springs extending between and connected at opposite ends respectively to the members to enable movement of the work member relative to the support member, and power means connected to and for moving the work member, the improvement residing in means connecting the ends of the coil springs to the members, each connecting means including a plug-like connector element of axially compressible, diametrically expansible elastomer material closely received coaxially within the end turns of the associated coil spring, and tension means connected between each element and the proximate member for axially compressing the element to cause it to expand diametrically into gripping engagement with its coil spring end, each element, before axial compression, having an outer annular generally toroidal surface predisposing said element toward uniform multi-directional diametric expansion when axially compressed.

-TReft'erences Cited UNITED STATES PATENTS 2,706,400 4/1955 Unholtz 73-67 3,169,757 2/1965 Roder et al 26760 FOREIGN PATENTS 509,121 7/1939 Great Britain.

JOHN PETO, Primary Examiner. 

